****HELP*** OMC I/O Sterndrive

[btsholes]

Ok I have a 1984 Arrivee Barbarian with a Chevy 350 small block. I just replaced the cam shaft lifters and fuel pump. We took it out today and it fired right up. Idled well but noticed a knocking noise. Went back to shore checked it out to see if it sounded like a rod.....not sure? Went back into the water temp was overheating loss power and smoke came from the engine. I am thinking I just blew my engine....got home thought I would see if it would start and it fired right up. I am think maybe bad water pump impelller which is making it overheat.....suggestions?

 

[Howard Sterndrive]

Re: ****HELP*** OMC I/O Sterndrive

start with a compression test. how old is the impeller?

 

[btsholes]

Re: ****HELP*** OMC I/O Sterndrive

I don't know how old the impeller is, We just bought the boat about a month ago. I am just concerned if the lack of a proper pump or impeller can cause a knocking noise? Thank you for your help!

 

[Howard Sterndrive]

Re: ****HELP*** OMC I/O Sterndrive

hard to troubleshoot a "knock" over the internet, but when an engine overheats, the pistons get bigger than the cylinders. The result is they rub, spall and eventually start welding themselves to the cylinders. stuff like rings break, and it knocks...will eventually seize. when it cools down it will run, but you have to check compression to see if that's what happened. the test will give you a starting point for diagnosis
The rubber impeller needs to be changed every few years. Bad idea to assume it's ok on a used boat (especially when previous owner tells you it was "just changed")
Especially important on a stringer mount drive like yours because the water pump shaft splines need to be greased- that gets addressed when the impeller is installed.

why did you replace the camshaft ?